Language change and code breaks

[Terry Reedy]

> I have changed my mind.  I think that if I had to start over, I
would
> indeed try my hands at a case-insensitive language aimed at teaching
> programming to beginners, with tools to enforce case consistency.
> Given that nobody else who currently uses Python thinks this is a
good
> idea, I then settled on a case-sensitive language with
case-preserving
> tools.  But now I think neither is worth fighting for.

As I understand the second option (tool optional), there is no need to
fight.  Just do it.  When you write your next-generation  interactive
CP4E IDE, which I really hope you get to do, you will, I think, want
to parse identifiers out of each line as entered, whether or not it is
immediately executed.  If a variable is used before being set, warn.
If a new var differs only in case from another, warn or prohibit.  If
usage conflicts with a known type, warn.  Etcetera.

Terry J. Reedy